In the U.S., coffee is essentially a human right. Even the most humble of blue-collar work environments has at least a "Mr. Coffee"-style drip machine, and most white-collar offices these days have a K-cup or other cartridge system that brews in seconds.
It's easy to brew coffee mechanically, because the optimal temperature is well below the boiling point. Whereas most black tea requires the water to be brought to a boil. Even a nice electric kettle takes forever compared to a $15 Mr. Coffee. Also, you need to drink tea right away, whereas coffee can sit on the burner for nearly an hour before non-snobs would think to throw it out.
So in the U.S., tea is more commonly consumed at home or in shops. Coffee is ubiquitous in the workplace, because it's far easier to brew in a hurry with machines (even cheap ones).
Never order tea while out in the US, you'll get a cup of cooling water with a teabag in a paper sachet by the side...
Unless you have a nice coffee machine, you're left to deal with a French press (too much effort, difficult for large rounds), or (gasp) instant coffee.
When out and about, if your drink is being made by a professional, it makes sense to have coffee over tea. Less faffing about removing tea bags, etc.